Commutator.



PATENTED FEB. 28, 1905.

H. A. KNOENBR.

GOMMUTATOR.

APPLICATION FILED JULY 25. 1904.

UNITED STATES Patented February 28, 1905.

PATENT OFFICE.

'HERMANN A. KNOENER, OF EAST ORANGE, NEIV JERSEY, ASSIGNOR TOOROOKER-IVHEELER COMPANY, OF AMPERE, NEW JERSEY, A CORPO- RATION OF NEWVJERSEY.

COMMUTATOR.

SPECIFICATION forming part of Letters Patent No. 783,965, dated February28, 1905.

Application filed July 25, 1904. Serial No. 218,051.

To all whom, it may concern.-

Be it known that I, HERMANN A. KNOENER, a citizen of the United Statesof America, and a resident of East Orange, county of Essex, and State ofNew Jersey, have invented certain new and useful Improvements inOommutators, of which the following is a specification.

The object of this invention is to produce a commutator the constructionof which is such that structural materials of greater strength and yetof less expensive character may be used and the parts may be morereadily and firmly assembled.

The commutator is cylindrical and is provided with commutator-bars suchas are ordinarily employed in dynamo-electrical machinery, wherein thecommutating-surfaces of the bars form the surface of a cylinder and eachbar lies along an element of the cylinder. The ends. of thecommutator-bars are clamped between flanges, and the flanges are screwedon reversely-threaded ends of a central tube, thereby holding the barsin place.

Referring to the accompanying sheet of drawingsavhich form a partof thisapplication, Figure 1 is an end ,view of my commutator. Fig. 2 is alongitudinal section on the line H II of Fig. 1. Figs. 3 and 4 arelongitudinal sections through the clamping-flanges. Fig. 5 is a sideview of the central tube. Fig. 6 is a perspective view of one of thecommutatorbars.

The commutator as illustrated in the drawings consists of a series ofcopper bars A of wedge-shaped section assembled with interposedinsulation M, usually mica, so as to form a cylindricalcommutating-surface, the bars being parallel to the axis of the cylinderand lying along parallel elements thereof, with the wide edges 0 formingthe commutator-surface. The ends of the bars are provided withnotches orV-grooves m. The bars are assembled about a tube or sleeve B. The tubeis cut to suitable length from accurately'drawn steel tubing-of regularcommercial sizes, which possesses greater tensile strength and costsless than cast-steel requiring to be turned,

which has heretofore been employed in commutator constructions whereinthe designs have required that one flange be integral with the sleeve.The ends of the tube are reversely threaded, a right-hand screw-thread1* being cut on the tube on one end and a lefthand screw-thread 6 beingcut on the tube on the other end. Flanges R and L, preferably of bearingmetal such as brass or bronze, in the form of nuts tapped withright-hand and left-hand threads, respectively, are screwed on the endsof the tube. Circular ribs t project from the sides of the flanges andare covered with insulating material M, preferably mica. The ribsproject into the notches in the ends of the commutator bars, the micabeing, however, interposed,and supportthe bars. By reason of the reversethreading of the two flanges they can be tightened simultaneously on thecommutator-bars by rotation relatively to the tube in the same directionor preferably by holding both flanges from rotation while the tube isrevolved. It therefore follows that the clamping is effected withoutdanger of dragging the commutator-bars and skewing them around at anangle, so that they will be out of parallelism with the axis of thecommutator. There is no danger of injuring the interposed mica betweenthe flanges and bars since there is no relative movement between these.Attention is also called to the fact that there is no sliding ofcontacting surfaces of parts relatively to each other except at thescrew-threads, and there is avoidance of all frictional action at agreater distance from the axis than the screw-threads in tightening theparts such as takes place when a nut is screwed against a flange orwasher. As

the threads are nearer to the axis, there is less leverage and slidingmovement, and the flanges are more readily and mo re li rml y 1t upagainst the commutator-bars with the application of a given amount ofturning force. The tube is notched at Z: to lit over a pin in thearmature-shaft on which the commutator is placed.

One end of each commutator-bar is slotted, as shown at w in Figs. Zand6, for the insertion and soldering therein of connections from screwedon the threaded ends of the tube and clamping the ends of thecommutator-bars, 5 and insulating; material interposed between theflanges and the bars, substantially as described.

Signed by me at East Orange, county of Essex. and State of New Jersey,this 16th day 20 of July, 1904.

HERMANN A. KNOENER.

Witnesses:

SAMUEL V. BALoiI,

E. R. DOUGLAS.

